The U.N. Security Council met on Sunday to discuss the killing of at least 108 people in the Syrian town of Houla, a sign of mounting outrage at the massacre that the government and rebels blamed on each other.
Images of bloodied and lifeless young bodies, lain carefully side by side after the onslaught on Friday, triggered shock around the world and underlined the failure of a six-week-old U.N. ceasefire plan to stop the violence.
Western and Arab states opposed to Syrian President Bashar al-Assad put the blame for the deaths squarely on the government.
Russia, which along with China, has vetoed Security Council resolutions calling for tougher action, said the "tragic" events in Syria deserve condemnation and called for a U.N. assessment of the violence there.
Russian Deputy U.N. Ambassador Alexander Pankin told reporters Moscow was skeptical about suggestions that the Syrian government was behind the massacre, saying it appeared most of the victims were killed with knives or shot at point-blank range.
British Ambassador Mark Lyall Grant disagreed.
"It seems quite clear that the massacre in Houla was caused by heavy bombardment, by government artillery and tanks," Lyall Grant said.
The United Nations believes that at least 108 people were killed, U.N. peacekeeping chief Herve Ladsous.
Moscow rejected a British and French proposal for a Security Council statement on the Houla massacre on Saturday, demanding a briefing from the head of the U.N. observer mission, General Robert Mood, first.
Security Council diplomats said on Sunday they hoped to agree on some kind of condemnation of the massacre, though Russia was clearly at odds with the Western powers regarding who was to blame.
In his public comments so far, Mood called the killings "a very tragical expression" of the situation in Syria, but refrained from apportioning blame.
"For myself, I have had patrols on the ground all the day yesterday afternoon and today we are gathering facts on the ground and then we will draw our own conclusions," Mood told the BBC in a telephone interview on Sunday.
"The sight like the one that now has been played out in Houla, it hits the stomach, it's really an attack on the future of the Syrian people. There are still those in Syria who believe the use of violence and quite deplorable use of violence serves their own self-interest," Mood said.
The U.N. observers confirmed the use of artillery, which only Assad's forces have, but did not say how all the victims died.
Syrian authorities blamed "terrorists" for the massacre, among the worst carnage in the 14-month-old uprising against Assad, which has cost about 10,000 lives.
"Women, children and old men were shot dead. This is not the hallmark of the heroic Syrian army," Foreign Ministry spokesman Jihad Makdesi told reporters in Damascus.
"HERDING US LIKE SHEEP"
But U.N. and Arab League envoy for Syria, Kofi Annan, and U.N. Secretary-General Ban Ki-moon accused the Syrian government of using artillery in populated areas.
"This appalling and brutal crime involving indiscriminate and disproportionate use of force is a flagrant violation of international law and of the commitments of the Syrian Government to cease the use of heavy weapons in population centers and violence in all its forms," they said in a joint statement on Saturday.
Annan's views and the briefing by Mood are likely to be very influential at the Security Council.
Opposition activists said Assad's forces shelled Houla after a protest and then clashed with fighters from the Sunni Muslim-led insurgency.
Activists say Assad's "shabbiha" militia, loyal to an establishment dominated by members of the minority Alawite sect, then hacked dozens of the victims to death, or shot them.
Maysara al-Hilawi said he saw the bodies of six children and their parents in a ransacked house in the town.
"The Abdelrazzak family house was the first one I entered. The children's corpses were piled on top of each other, either with their throats cut or shot at close range," Hilawi, an opposition activist, said by telephone from the area.
A video distributed by activists showed an injured woman, who said she had survived the massacre, blaming shabbiha militiamen for the carnage.
"They entered our homes ... men wearing fatigues herding us like sheep in the room and started spraying bullets at us," the woman said. "My father died and my brother, my mother's only son. Seven sisters were killed," the woman said lying next to another injured woman and near a baby with a chest wound.
The White House said it was horrified by credible reports of brutal attacks on women and children in Houla.
"These acts serve as a vile testament to an illegitimate regime that responds to peaceful political protest with unspeakable and inhuman brutality," a White House spokesman said.
The Gulf Cooperation Council of Sunni-led monarchies accused Assad's soldiers of using excessive force and urged the international community to "assume its responsibilities to halt the daily bloodshed in Syria."
EU foreign policy chief Catherine Ashton spoke of a "heinous act perpetrated by the Syrian regime against its own civilian population" in a statement on Sunday. The head of the European parliament said it could amount to a war crime.
On Sunday, at least 30 people were killed when Syrian army tanks shelled residential neighborhoods in the city of Hama that have been serving as bases for rebel attacks against loyalist forces, opposition activists said. The reports could not be verified independently.
Although the ceasefire plan negotiated by Annan has failed to stop the violence, the United Nations is nearing full deployment of a 300-strong unarmed observer force meant to monitor a truce.
The plan calls for a truce, withdrawal of troops from cities and dialogue between government and opposition.
Syria calls the revolt a "terrorist" conspiracy run from abroad, a veiled reference to Sunni Muslim Gulf powers that want to see weapons provided to the insurgents.
The United Nations has accused Assad's forces and insurgents alike of grave human rights abuses, including summary executions and torture.